Steering mechanism for hydrofoil boats



Dec. 27, 1966 v "r. o. JONES 32%,052

STEERING MECHANISM FOR HYDROFOIL BOATS Filed May 13, 1965 3 Sheets-Sheetl INVENTOR. TED 0. JONES ATTORNEYS Dec. 27, 1966 T. o. JONES STEERINGMECHANISM FOR HYDROFOIL BOATS 3 SheetsSheet 2 Filed May 13, 1965INVEN'IOR. 75D 0, JONES 13 Yfl Dec. 27, 1966 'r. o. JONES STEERINGMECHANISM FOR HYDROFOIL BOATS 5 Sheets-Shem, 5

Filed May 15, 1965 IN VEN'I OR 0. JONES ATTOANFYS' United States Patent3,294,052 STEERENG MECHANISM FOR HYDROFOIL BOATS Ted 8. .lones,Kennydale, Wash., assignor to Hydro Marine Incorporated, Houghton,Wash., a corporation of Washington Filed May 13, 1965, Ser. No. 455,4609 Claims. (Cl. 114--66.5)

The present invention relates to hydrofoil boats, and more particularlyto steering mechanism for hydrofoil boats of the type characterizedgenerally by a displacement hull and a pair of surface piercinghydrofoils, one of which is supported below a forward portion of suchhull and the other of which is supported below the stern portion of thehull, and to steering techniques involving such mechanism.

Typical hydrofoil boats of the surface piercing hydrofoil type aredisclosed by: Von Schertel, US. Patent No. 2,720,180; Vertens, US.Patent No. 2,767,678; and Vertens, US. Patent No. 2,842,083.

Surface piercing hydrofoils have inclined, dihedrally related sideportions interconneced by a substantially horizontal central portion.During flying of the boat only the central portions and the lower areasof the inclined side portions are normally submerged, and the mainlifting force is provided by the central portions. Upon any tendency ofthe boat to tilt or roll about its longitudinal axis to one side, theinclined foil portions on such side are immersed more than normal andexert a stabilizing lift on the boat, tending to maintain it on an evenkeel.

Hydrofoil boats of the surface piercing hydrofoil type areconventionally steered by a rudder located generally at the stern of theboat, but with some difficulty. To effect a turn, the rudder is rotatedin the opposite rotational sense to the desired direction of turn. Thewater in the path of the rudder is then turned thereby and acceleratedinto a new direction, creating a lateral cornponent of force tending toswing the stern sideways in a direction opposite to the turn, and topoint the bow into the turn. However, since the boat has a high centerof gravity, and the rudder is offset a substantial distance below it,the water reaction force acting on the rudder causes the boat to bankinto the turn. As this happens the inside inclined side portion of theforward hydrofoil becomes more submerged than usual and produces forceswhich oppose turning.

A principal object of the present invention is to provide a steeringsystem operable to keep a hydrofoil boat of the surface piercinghydrofoil type on a substantially even keel while making a turn, so thatno major hydrofoil interference with turning occurs.

According to the present invention, a turning or steering rudder isassociated with the forward hydrofoil. In preferred form, the supportstructure for the forward hydrofoil includes a vertical center strut,and such rudder is journaled for rotation generally at the rear edge ofsuch strut. To effect a turn, or to keep the boat on course when a windor current condition exists tending to push it off course, the rudder isrotated in the same rotational sense as the desired direction ofrelative turn. It then produces a lateral component of force by waterreaction which tends to push the bow portion of the boat relativelysideways. Since the forward rudder is located below the center ofgravity of the boat, it also produces a rotational (or roll) effecttending to bank the boat away from the turn. Such banking is in partchecked by the inclined portion of at least the forward hydrofoil on theoutside of the turn, but only in part. According to the invention, asecond or trim rudder is provided at the stern of the craft, at thecustomary location of conventional stern placed turning rudders. Thetrim rudder is used principally for correcting the lateral trim of3,29lfi52 Patented Dec. 2'7, 1966 "ice the boat. Its main purpose is toproduce a rotational moment in the vertical sense which acts inopposition to, and hence counters the rotational moment produced by theforward rudder. In order to do this, it normally is rotated in theopposite rotational sense to the direction of relative rotation of thebow. Therefore, it also produces a horizontal moment tending to swingthe bow relatively sideways in the desired direction. Hence, thehorizontal moments produced by the two rudders are additive and bothtend to rotate the boat horizontally in the same direction, whereas thevertical moments are opposite. The vertical moment produced by theforward rudder tends to roll the boat to one side, and the verticalmoment produced by the rear rudder tends to roll the boat to the otherside. According to the invention, turning or steering is effected mainlyby movement of the forward rudder, and then, in response to a tendencyof the boat to roll sideways, the rear rudder is operated so as toproduce a moment that opposes the undesirable roll effect of the forwardrudder.

According to this invention, a sideways rolling tendency produced by anuneven lateral distribution of passengers and/ or cargo Weight (i.e.more weight is situated on one side of the longitudinal axis than on theother) may also be countered by the trim rudder.

These and other features, advantages, objects and capabilities ofsteering equipment according to the present invention will be apparentfrom the following description of a typical form thereof, as adapted foruse on a catamaran hull, for example, taken together with theaccompanying illustrations, wherein like numerals refer to like parts,and wherein:

FIG. 1 is a perspective view of a boat hull and hydrofoil combinationembodying the teachings of the present invention, with the boat hullbeing shown in broken lines and the hydrofoil assemblies in full line;

FIG. 2 is a side elevational view of the boat hull and hydrofoilcombination of FIG. 1, with parts in section;

FIG. 3 is a cross-sectional view through the boat bull in the vicinityof the front edge of the rear rudder, taken substantially along line 33of FIG. 2;

FIG. 4 is a cross-sectional view through the boat hull in the vicinityof the rear edge of the front rudder, taken substantially along line 4-4of FIG. 2;

FIG. 5 is a fragmentary perspective view of the central portion of theforward hydrofoil assembly, showing a typical way of mounting the centerstrut onto the support bar of such assembly, a typical control mechanismfor the rudder post, and the relationship of the forward rudder to thecenter strut and the central portion of the hydrofoil;

FIG. 6 is a view taken substantially along line 66 of FIG. 5, showing inplan the worm gear and arcuate pinion portions of the illustrated formof control mechanism for the rudder post;

FIG. 7 is a view taken substantially along line 7-7 of FIG. 5, showingthe cross-sectional configuration of the portion of the forward rudderthat is situated above the hydrofoil;

FIG. 8 is a view taken substantially along line 88 of FIG. 5, showingthe manner in which the hydrofoil is cut away or notched immediatelyrearwardly of the center strut, so as to permit limited pivotal movementof the rudder, and showing in full line the rudder in a straight aheadposition, and in broken line such rudder in both its full left turn andits full right turn position;

FIG. 9 is a somewhat diagrammatic top plan view of the boat of FIGS. 1and 2, showing the front rudder turned so as to effect a left turn, andthe rear rudder turned so as to correct the lateral trim of the boat andkeep it on a substantially even keel throughout the turn;

FIG. 10 is a fragmentary side elevational view taken in the vicinity ofthe mounting apparatus for the rear hydrofoil assembly, such viewincluding a full line showing of the various components of such assemblyin their in use positions, and a broken line showing of such componentsin their retracted positions;

FIG. 11 is a view like FIG. 10, but of the mounting apparatus for theforward hydrofoil assembly, and further including a broken line showingof the various components of such assembly in the position which theytake upon the breaking of a shear pin; and

FIG. 12 is a fragmentary perspective view of an intermediate portion ofthe telescopic brace shown by FIG. 11, taken in the vicinity of theshear pin, and showing the shear pin spaced outwardly away from theopenings provided for it.

Referring more specifically to the several figures of the drawing, FIGS.1 and 2 show a catamaran type hull 10 equipped with a front or bowhydrofoil assembly 12 and a rear or stem hydrofoil assembly 14. The hull10 and both hydrofoil assemblies 12, 14 are symmetricaly constructedabout a fore and aft and vertically extending plane of symmetry y (FIGS.3 and 4).

The drive assembly for the craft comprises an engine 16 located in thestern area of the hull 10, a drive shaft 18 interconnected between theengine 16 and a transmission 20, and a propeller shaft 21 interconnectedbetween the transmission 20 and a propeller 22. The propeller shaft 21is supported near its middle and at its after end by means of bearings24, 26 mounted at the lower ends of support struts 28, 30, respectively.

The front hydrofoil assembly 12 comprises a hydrofoil 32 extending abeamof hull 10, below the bow portion thereof. The support structure forhydrofoil 32 may comprise a horizontal support member 34 mounted so asto extend laterally through and be supported by the bow portion of thehull 10. A center strut 36 is rigidly interconnected between themid-portion of the support member 34 and the mid-portion of hydrofoil32, and a pair of side struts 38, 40 are rigidly interconnected betweenthe ends of support member 34 and outboard portions of hydrofoil 32.

Hydrofoil 32 is preferably of polyhedral form. The illustrated form isshown (FIG. 4, for example) as comprising a generally horizontal orslightly dihedral central portion, composed of a pair of foil sections42, 44 set at a relatively low degree of deadrise (about 10, forexample), and inclined side portions 46, 48, each set at a relativelyhigh degree of deadrise (about 35, for example).

According to the present invention, a rudder 50, herein referred to aseither the forward or turning rudder, is journaled for horizontalrotation generally at the rear edge of the center strut 36. Thejournaling means may comprise a pair of vertically spaced apart knucklehinges, each including a central eye 52 projecting rearwardly from thestrut 36, and entering into a jaw formed between two corresponding eyesprojecting forwardly from the leading edge of the upper portion ofrudder 50. A rudder post 58 extends through the aligned eye openings andserves as a pin for retaining the parts together. So that rotation ofrudder post 58 will in turn cause rotation of rudder 50, the rudder post58 is affixed to the eyes 54, 56, and freely rotatable in the eyeopenings of members 52.

The mechanism for rotating post 58 may comprise a sector gear 60 or thelike afiixed to the upper end of rudder post 58, a worm gear 62 in meshwith gear 60, and a flexible shaft 64 for rotating worm gear 62. A gearhousing 66 may be provided at the rear edge and near the top of strut 36to provide an enclosure for the gears 60, 62 (FIGS. and 6). The upperendportion of the rudder post 58 extends through an opening provided inthe bottom of such housing 66, and the gear 60 is keyed or otherwiseaflixed to such upper end portion of post 58. A flexible casing orsheath 68 for shaft 64 may lead and be joined to a side portion of thehousing 66, and the control shaft 64 may project from said sheath 68 andextend through an aperture provided in the side wall of housing 66, andat its end be secured to an end of worm gear 62.

As shown by FIG. 1, the flexible control shaft 64 and its sheath 68extend from the gear housing 66 to a similar type of gear assembly (i.e,a worm gear meshing with a sector gear) serving to drivinglyinterconnect the flexible shaft 64 with the lower end of a steering postforming a part of a steering wheel assembly 70.

The rudder 50 is divided generally at the level whereat the hydrofoil 32meets the lower end of center strut 36 int-o upper and lower portions,designated 72 and 74, respectively. The upper portion 72 isnon-counterbalanced, i.e. its leading edge substantially coincides withthe pivotal axis. The lower portion of rudder 50 extends forwardly aswell as rearwardly of said rotational axis, and hence iscounterbalanced. The rear edge of rudder 50, the leading edge of therudders upper portion 72, and the leading edge of the portion of strut36 that is above the water line during flying may all be blunt, asillustrated. However, it is preferred that the leading edge of at leastthe portion of strut 36 that is in the water during flying, and theleading edge of the rudders lower portion 74 (which of course is alsosubmerged during flying), be wedge-shaped. As illustrated by FIG. 8, forexample, the side surfaces of these submerged portions curve together asthey extend forwardly, and they meet at a relatively sharp acute angle.In the drawing a transition line between the two forward edge forms ofstrut 36 is indicated at 76.

The rear hydrofoil assembly 14 is shown to be similar in its makeup tothe forward assembly 12. In FIGS. 1 and 3, for example, it is shown ascomprising a surface piercing hydrofoil 78 composed of laterally andoutwardly inclined side portions 80, 82, and a horizontal centralportion 84 interconnected between the respective inboard ends of suchside portions 80, 82.

The support structure for the rear hydrofoil 78 includes a horizontalsupport member 86 mounted so as to extend laterally through and besupported by the stern portion of the hull 10, a vertical center strut88, and a pair of vertical side struts 90, 92. The vertical center strut88 is rigidly interconnected between the mid-portion of support member86 and the mid-portion of hydrofoil 78. The vertical side struts 90, 92are rigidly connected at their upper ends to the ends of support member86, and at their lower ends to outboard portions of the hydrofoil sideportions 80, 82.

According to the invention, a trim rudder 94 is journaled for horizontalrotation substantially at the rear edge of center strut 88. Thejournaling means may be essentially the same as the journaling meansassociated with the forward hydrofoil assembly 12, and it includes arudder post 96. The upper end of rudder post 96 is shown to extend intoa gear housing 98 containing a worm and sector gear drive means, or thelike. A flexible control line means 100 drivingly interconnects saiddrive means with a complementary drive means located at the lower end ofa steering post forming a part of a second steering wheel assembly 102(FIG. 1). By way of typical .and therefore non-limitive example, thesteering post for steering wheel assembly 102 may be tubular, and thesteering post for steering wheel assembly 70 may extend concentricallytherethrough, with adjacent inner and outer steering wheels 104, 106being provided, for the convenience of the operator.

The preferred operation of the steering mechanism will now be described.Let it be assumed that the rudders 50, 94 are aligned with each otherand with their respective support struts 36, 88 and that the boat istraveling straight ahead. When it is desired to make a turn, steeri-ngwheel 104 is appropriately rotated in order to cause rotation of forwardrudder 50 in the same rotational sense as the direction of turn. Thus,if a left or counterclockwise turn is to be made (FIG. 9), the rudder 50is rotated counterclockwise. The water in the path of rudder 50 is thendeflected thereby, causing a change in momentum, and a force is exertedon the rudder 50. This force is transmitted from the rudder 50 throughits support structure to the bow, and moves the bow sideways into theturn. However, since the rudder is located well below the center ofgravity C of the craft, the water reaction also produces a significantmoment acting at a right angle to the longitudinal axis of the craft,which tends to roll the craft sideways about its longitudinal center andcause it to bank away from the turn. The inclined side portions of thehydrofoils on the outside of the turn tend to resist such rolling, butby themselves do not prevent it from occurring.

According to the present invention, after the forward rudder 50 isoperated in the manner described, for effecting a turn, the rear rudder94 is operated for the purpose of substantially keeping the boat levelor on an even keel throughout the turn. Referring again to FIG. 9,rotation of the rudder 94 in the opposite rotational sense to thedesired direction of turn causes it to produce a horizontal rotationalforce by water reaction that is additive to the horizontal rotationalforce produced by the turning rudder 50. Thus, when turned in thisdirection the rear rudder 94 aids the forward rudder 50 in causing theboat to turn horizontally. However, since like rudder 55) it too isspaced a substantial distance below the center of gravity C, rudder 94also produces a moment acting at a right angle to the longitudinalcenter of the craft, but in the opposite direction to the roll producingmoment created by rudder 50. Thus, rudder 94 may be used for producing amoment that will oppose or counter the roll effect of the forward rudder56. According to the present invention, it is used primarily for thispurpose; the assistance it gives to rudder 50 by way of pushing thestern sideways so as to swing the bow into the turn is secondary. Theoperator moves rudder 50 for causing the boat to turn. Then in responseto the tendency of the boat to roll, caused by rudder 50, he movesrudder )4 to prevent roll.

In FIG. 9, vertical arrow symbols (i.e. a circle with a dot in itrepresenting upward movement and a circle with a cross in itrepresenting downward movement) are used for indicating the direction ofsideways roll tendency produced by the front and rear rudders 5t), 94,respectively.

In addition to turning, the forward rudder 50 is used for steering ingeneral. For example, it is used for the purpose of maintaining the boaton a desired course when there is a wind or current condition presenttending to push it off course. The rudder 50 is rotated horizontally anamount sufficient to cause a lateral component of force by waterreaction of a sufficient magnitude to hold the bow substantially oncourse. The boat is not actually rotated (horizontally) into a newdirection, as in a turn, but it is continuously being rotated relativeto the direction of wind or current travel. As during turning, thehorizontal moment is attended by a vertical moment tending to roll theboat sideways. Also as during turning, the stern rudder 94 is operatedin response to this rolling tendency for the purpose of countering itand maintaining proper lateral trim of the boat. The stern rudder 94 mayalso be used for maintaining the desired lateral trim of the boat whenthe tendency for the boat to roll sideways is due at least in part byother causes, such as an uneven lateral distribution of passenger and/orcargo weight, for example.

As illustrated by FIGS. 5, 7 and 8, for example, the rear edge of strut36 and the rudder post 23 are both spaced forwardly of the rear edges ofhydrofoil sections 42, 44. The sections 42, 44 are notched in thevicinity of the rear edge of strut 36 so as to make it possible to turnthe rudder. In the illustrated arrangement the notch is in the form ofabout a ninety degree (90) d V-cut, with about half of such cut locatedon each side of strut 36.

As perhaps best shown by FIGS. 1 and 2, the propeller 22, and theforward part of the lower portion of rudder 94 both extend below thecentral portion of the rear hydrofoil '78. As a consequence, thehydrofoil acts as a cavitation plate for both of these elements, and noadditional or independent cavitation plate means (not a part of thehydrofoil 78) is necessary. The midportion of the forward hydrofoil 32also serves as a cavitation plate for the leading part of the lowerportion 74 of rudder 50.

Tests which I conducted emperically showed that a boat equipped withsurface piercing hydr-ofoils can be turned much easier by means of afor-ward rudder in place of a conventional stern rudder, and thatturning is further improved when a stern rudder is used in conjunctionwith a forward turning rudder for keeping the craft substantially on aneven keel throughout the turn. Another advantage of the forward turningrudder is that it operates on substantially clean Water. The lower,submerged portion of strut 36, the inboard end portions of hydrofoilsections 42, 44, and its own leading edge, are the only parts associatedwith the boat that can cause water disturbance ahead of rudder 50, andeach of these parts has a knife-like leading edge and a slim profile sothat it will cut through the water and produce essentially noturbulence. This is not the case with a conventional stern locatedturning rudder, as it is located in the prop wash which is veryturbulent water.

Preferably, the hydrofoil assemblies 12, 14 are retractably mounted sothat they can be swung upwardly into substantially horizontal, out ofthe way, retracted positions, to facilitate handling and transporting ofthe boat when out of the water. As previously described, the supportmember 34 of the forward hydrofoil assembly 12 extends transverselythrough the bow portion of the hull l9, and the horizontal supportmember as for the rear hydrofoil assembly 14 extends transverselythrough the stern portion of the hull 10. The members 34, 86 may bemounted for rotation by means of bearings I08, 110, respectively (FIGS.3 and 4).

The assemblies i2, 14 are provided with separate releasable means forbracing them against movement. The bracing means for the forwardhydrofoil assembly 12 may comprise a lever arm 112 rigidly secured tomember 34 and arranged to depend downwardly therefrom when the assembly12 is in its position of use. An anchor 114 is affixed relative to hull10 and spaced rearwardly of, and in substantial alignment with, thelever 112. A telescopic brace 116 is rigidly interconnectable betweenthe lower end of lever 112 and the anchor 114, to support or brace theassembly 12 against pivotal movement. In FIG. 11, the telescopic brace116 is shown to comprise a tubular outer section 118 and an innersection 120 telescopically received therein. Aligned openings areprovided through the side walls of outer section 1 .18, and a pair oftransverse openings are formed in the inner section 129 at axiallyspaced locations. The first of the openings in section 126 is positionedsuch that when it is put in alignment with the openings in outer section113, the support struts 36, 33, 4% are substantially vertical, and thehydrofoil 32. is properly oriented for use. When the second opening insection 120 is aligned with the openings in section 118, the struts 3d,38, 40 are substantially horizontal. A locking pin 122 is used forlocking the sections 118, 12% together.

When it is desired to move the forward hydrofoil assembly from its inuse to its retracted position, the locking pin 122 is removed and theassembly 12 is swung forwardly and upwardly until the second opening ininner section 120 of the telescopic brace 116 is aligned with theopenings in the outer section 118. The pin 122 is then inserted throughthis new set of aligned openings, and when in place it serves to lockthe forward assembly 12 in its retracted position (FIG. 11).

Pin 122 is designed so that it will shear and permit a rearward collapseof the forward hydrofoil assembly 12 in the event such assemblyencounters an obstruction in the water. Of course, the pin 122 isdesigned so that it will withstand the forces put on it by minorobstructions, and to shear when such obstructions are sufliciently largeenough that damage of the hydrofoil assembly 12 would be likely. Whenpin 122 is sheared, the hydrofoil assembly 12 swings rearwardly (FIG.11) and the inner section 120 of brace 116 moves further into the outersection 118. As best shown by FIG. 4, the lever arm 112, the anchor 114and the telescopic brace 116 may all be located in one of the two hullparts of the boat, if a catamaran hull is involved, as illustrate-cl.

FIG. 11 presents a solid line showing of the in use position ofcomponents 112, 116, 38. The normal retracted position is shown inbroken lines immediately above the solid line showing, and the rearwardretracted position (occurring when pin 122 is sheared) is shown inbroken lines at the top of the figure.

Support member 86 for the rear hydrofoil assembly 14 is provided with alever 124 arranged to project upwardly above the member 86 when thehydrofoil assembly 14 is down in its in use position. An anchor 126,afiixed relative to the hull 10, is located forwardly of and in linewith the lever 124, and a telescopic brace 128 is rigidlyinterconnectable between the upper end of lever 124 and the anchor 126.Like brace 116, the brace 128 includes a tubular outer section 130, aninner section 132, and such sections are lockable together by means of apin 134, insertable through aligned openings in the outer section 130and a selected one of a pair of axially spaced openings formed in theinner section 132. In the illustrated embodiment, when the pin 134 islocated in the forward opening in section 132, the hydrofoil assembly114 is in its normal position of use. When the pin 134 is in the rearopening in section 132, the assembly 14 is swung rearwardly and upwardlyfrom its position of use, into a generally horizontal retracted position(FIG. Pin 134 also functions as a shear pin and is designed to breakwhen the submerged portions of hydrofoil assembly 14 encounter obstaclescapable of producing destructive forces.

In FIG. 10, the in use position of components 90, 124, 128 is shown inthe upper portion of the view by solid lines. The retracted position ispresented below such showing, in broken lines.

The forwardly located turning rudder feature of the present invention isnot limited to use on a central strut, but may also be used on one orboth of a pair of intermediate struts, such as those shown by FIG. 2 ofthe aforementioned Vertens U. S. Patent No, 2,767,678, for example. Thetrim rudder at the stern of the craft may also be provided on one orboth of a laterally spaced pair of intermediate struts. Furthermore,application of the present invention is not at all limited to acatamaran type hull, but rather the forward turning rudder, and suchrudder in combination with an after trim rudder, may be advantageouslyemployed with other types of hulls, such as a conventional vee, shallowvee or rounded bottom hull, or a trimaran hull, for example. Also, ahydraulic or electrical control system leading from the steering wheelassemblies to the drive means at the upper ends of the respective rudderposts may be employed in place of the mechanical drive system that isillustrated. The only requirement in an installation wherein the frontand rear hydrofoil assemblies are retractable, is that the control linemeans he flexible and of such a length that they remain slack duringmovement of the hydrofoil assemblies between their respective in use andretracted positions.

The foregoing is to be considered as being merely illustrative oftypical structural embodiments incorporating the principles of thepresent invention, and is therefore to be construed as not limitive innature. Since changes, variations, and modifications in the form,construction and the arrangement of the steering mechanism shown anddescribed may be had without departing from the spirit of the invention,it is to be understood that the invention is to be limited solely by thescope of the appended claims.

What is claimed is:

1. A water craft comprising: an elongated hull; front and rear hydrofoilassemblies, each comprising a transverse hydrofoil spaced below thehull, and including a relatively fiat central portion and surfacepiercing side portions extending both upwardly and laterally outwardlyfrom and on opposite sides of said central portion, and supportstructure for said hydrofoil interconnected between said hydrofoil andthe hull, with at least the support structure for the forward assemblyincluding a substantially vertical strut disposed below the hull, and aturning rudder having a forward portion journaled for horizontalrotation generally at the rear edge of said strut, with at least agreaterportion of said rudder being disposed rearwardly of the rear edgeof said strut; and propulsion means for said craft situated rearwardlyof said front hydrofoil assembly.

2. A water craft comprising: a displacement hull symmetricallyconstructed about a fore and aft and vertically extending plane ofsymmetry; front and rear hydrofoil assemblies respectively situatedforwardly and rearwardly of the center of gravity of said craft, andeach comprising a transverse hydrofoil spaced below the hull, andincluding a relatively flat central portion and surface piercing sideportions extending both upwardly and laterally outwardly from and onopposite sides of said central portion, and support structure for saidhydrofoil interconnected between said hydrofoil and the hull, with atleast the support structure for the forward assembly including asubstantially vertical strut located in said lane of symmetry, and arudder having a forward portion journaled for horizontal rotationgenerally at the rear edge of said strut, with at least a greaterportion of said rudder being disposed rearwardly of the rear edge ofsaid strut; and propulsion means for said craft situated rearwardly ofsaid front hydrofoil assembly.

3. A water craft comprising: a displacement hull symmetricallyconstructed about a fore and aft and vertically extending plane ofsymmetry; front and rear hydrofoil assemblies respectively situatedforwardly and rearwardly of the center of gravity of said craft, andeach comprising a transverse hydrofoil spaced below the hull, and including a relatively flat central portion and surface piercing sideportions extending both upwardly and laterally outwardly from and onopposite sides of said central portion, support structure interconnectedbetween said hydrofoil and the hull and including a substantiallyvertically intermediate strut extending below the hull, and a rudderhaving a forward portion journaled for horizontal rotation generally atthe rear edge of said strut, with at least a greater portion of saidrudder being disposed rearwardly of the rear edge of said strut; anddrive means for said craft including a propeller situated substantiallyimmediately forward of and in line with the rear rudder, andsubstantially rearwardly of said front hydrofoil assembly.

4. A water craft comprising: a catamaran hull having a central tunnelarea; front and rear hydrofoil assemblies respectively situatedforwardly and rearwardly of the longitudinal center of said hull, andeach comprising surface piercing hydrofoil means spaced below the hull,and support structure interconnected between said hydrofoil means andthe hull, with at least the support structure for the forward assemblyincluding a substantially vertical center strut, means mounting theupper end of said strut on the hull, in the vicinity of the tunnel roof,at the center of said tunnel, and a rudder journaled for horizontalrotation immediately rearwardly of said strut; and means for propellingthe craft forwardly.

5. In a water craft of a type comprising a catamaran hull having alongitudin-ally extending, laterally arched, central tunnel area formedbetween a pair of hull parts; surface piercing hydrofoil means forhydrodynamically lifting such hull out of the Water during forwardacceleration of the craft, and for hydrodynamically supporting such hullin a position above the water during cruising at high speed travel ofthe craft, said hydrofoil means including a bow section hydrofoilassembly comprising a hydrofoil member spaced a substantial distancebelow and extending abeam of said hull, and support structureinterconnected between said hydrofoil member and the hull, said supportstructure including a center strut and a pair of outboard struts; arudder journaled for horizontal rotation substantially immediatelyrearwardly of the center strut; control means for rotating said rudder;means mounting said hydrofoil assembly for pivotal movement between aposition of use wherein the struts are substantially vertical, and aretracted position wherein said struts are substantially horizontal andthe center strut is located in the tunnel, between the hull parts, andmeans normally locking the hydrofoil assembly in its in use position.

6. The combination of claim 5, the rudder control means including arudder post extending generally vertically in line behind said centerstrut above the rudder, and being attached to said rudder, and means forrotating said rudder post comprising drive means mounted on said centerstrut, near the upper end thereof, operator control means, and aflexible control line means interconnected between said operator controlmeans and said drive means, and being of a sufficient length andflexibility to permit it to remain slack during movement of thehydrofoil assembly between its in use and retracted positions.

7. A water craft comprising: an elongated hull; front and rear hydrofoilassemblies, each comprising a surface piercing hydrofoil means spacedbelow the hull, and support structure for same interconnected betweensaid hydrofoil means and the hull, with at least the support structurefor the forward assembly including a substantially vertical strutdisposed below the hull, and a turning rudder journaled for horizontalrotation generally at the rear edge of said strut, and including anon-counterbalanced upper portion extending above said hydrofoil meansand a counterbalanced lower portion depending downwardly below the levelof said hydrofoil means at the strut; and propulsion means for saidcraft situated rearwardly of said front hydrofoil assembly.

8. A water craft comprising: a displacement hull symmetricallyconstructed about a fore and aft and vertically extending plane ofsymmetry; front and rear hydrofoil assemblies respectively situatedforward and rearwardly of the center of gravity of said craft, and eachcomprising a surface piercing hydrofoil means spaced below the hull, andsupport structure for same interconnected between said hydrofoil meansand the hull, with at least the support structure for the forwardassembly including a substantially vertical strut located in said planeof symmetry, and a rudder journaled for horizontal rotation generally atthe rear edge of said strut, and including a non-counterbalanced upperportion extending above said hydrofoil means and -a counterbalancedlower portion extending downwardly below the level of said hydro foilmeans at the strut; and propulsion means for said craft situatedrearwardly of said front hydrofoil assembly.

9. The combination of claim 8, wherein at least that portion of thestrut disposed immediately forwardly of the upper portion of the rudder,and the lower portion of the rudder, each include side surfaces whichcurve together and meet at a relatively sharp acute angle, giving suchportions a relatively sharp leading edge.

References Cited by the Examiner UNITED STATES PATENTS 1,529,036 3/1925Richey 114-66.5 1,780,767 11/1930 Scott-Paine 114-163 2,720,180 10/1955Von Schertel 114-665 2,791,195 5/1957 Almiquist et a1. 114-665 3,137,2606/1964 Harris et a1 114-665 FOREIGN PATENTS 1,157,956 11/1963 Germany.

FERGUS S. MIDDLETON, Primary Examiner.

ANDREW H. FARRELL, MILTON BUCHLER,

. Examiners.

1. A WATER CRAFT COMPRISING: AN ELONGATED HULL; FRONT AND REAR HYDROFOILASSEMBLIES, EACH COMPRISING A TRANSVERSE HYDROFOIL SPACED BELOW THEHULL, AND INCLUDING A RELATIVELY FLAT CENTRAL PORTION AND SURFACEPIERCING SIDE PORTIONS EXTENDING BOTH UPWARDLY AND LATERALLY OUTWARDLYFROM AND ON OPPOSITE SIDES OF SAID CENTRAL PORTION, AND SUPPORTSTRUCTURE FOR SAID HYDROFOIL INTERCONNECTED BETWEEN SAID HYDROFOIL ANDTHE HULL, WITH AT LEAST THE SUPPORT STRUCTURE FOR THE FORWARD ASSEMBLYINCLUDING A SUBSTANTIALLY VERTICAL STRUT DISPOSED BELOW THE HULL, AND ATURNING RUDDER HAVING A FORWARD PORTION JOURNALED FOR HORIZONTALROTATION GENERALLY AT THE REAR EDGE OF SAID STRUT, WITH AT LEAST AGREATER PORTION OF SAID RUDDER BEING DISPOSED REARWARDLY OF THE AREAEDGE OF SAID STRUT; AND PROPULSION MEANS FOR SAID CRAFT SITUATEDREARWARDLY OF SAID FRONT HYDROFOIL ASSEMBLY.